Question

Find the highest number which divides 30, 45 and 60

• A. 30
• B. 6
• C. 60
• D. 15

Answer 1

The correct option is D 15

To find the greatest number which divides 30, 45 and 60 we have to find the HCF of 30, 45 and 60.

$\begin{array}{cc}5& 30,45,60\\ 3& 6,9,12\\ & 2,3,4\end{array}$

Since there are no common factors for 2, 3, 4 we cannot factorise it further.

Hence, the highest number which divides 30, 45 and 60 is
$=3\times 5=15$